Reciprocating engine.



VWNILIJIAM A. PITT, NEW YORK, N, Y.

RECIPROGATING ENGINE.

Specification of Letters Patent.

Application filed April 8, 1910.

Patented Aug. 18, 19114.

serial No. 554,238.

' nections is converted into rotary motion by the operation of a yoke which is attached to the piston and which engages with and upon an equilateral triangular cam, rigidly attached to the rotatable shaft. One form of such an engine, employing such a cam, is shown and described in Letters Patent No. 546,055, granted to me September 1t), 1895, the cam bein there shown in combination with four cylinders and pistons adapted to be operated by steam. The result of the ap` plication to such an engine of the herein described embodiment of the present invention is to increase `the etciency of an engine of this triangular-cam type, by clin'iinating a large part of the friction thereof, and in other ways. For instance, it is obvious that in the embodiment of my invention shown in the accompanying' drawings the outer yoke serves to guide the piston so that the same is always 'in line with the cylinder axis, and no connecting rod is necessary. Furthermore, this invention causes a dwell in the reciprocating movement of the piston at. the upper and lower ends of its stroke which is of great benefit in reciprocatine engines both of the internal .combustion and non-combustion fluid operated types.

I have shown the invention in connection with a two-cycle internal combustion en gine provided with one cylinder only in order to disclose and explain the great advantage of such an engine when operating a shaft by means of an equilateral triangular Cam; but I do not limit myself to engines of the internal combustion type, nor to an engine havlng one or any particular num.

ber of cylinders.

The invention consists of the novel construction, arrangementand combination of the various devices and parts hereinafter described and shown in the accompanying drawings. l In the said drawings, Figure 1 is a vertleal section, in the direction transverse to the shaft, of a two`cycle internal combus' tionengine, showing the position of the. opeizatmg parts at the beginning of a stroke; l' 1g. 2 1s a vertical section of the same taken parallel to the shaft; Fig. 3 is a vertical section of a modilied form of the invention: Fig. 4 is a view similar to Fif. 2 but showing all the moving parts at the end of the strok` as in Fig. 3; and Fig. 5 is merely a diagram showing an4 equilateral triangle which is the basis of the cam construction.

In carrying my invention into effect I provide a shaft 10, suitably journaled in the cam and yoke case or body of the engine` 11, or it' desired, in ordinary standard bear; ings as lil. I key or otherwise rigidly secure to this shaft an equilatcral triangular cam, l2. The three sides of the cam are `curved as shown in Figs. 1 and 3, the curves being arcs of circles of which the two sets of radii employed are at equal distance from the points of intersection of the sides of the lnisic-equilatcral triangle as shown in Fig. 5. On the inner walls ot' the body 1l of the engine ouideways 14, may he rovided in which freely slides a cam yo te l5, with power direction, and in this cam yoke freely slides a similar or secondary cam-yoke 16. The larger yoke 15 is in the shape of a parallelogram, while the smaller interior yoke 1G is square, the' interior individual side measurement being equal to the greatest distance measured by a line intersecting any one of the angles across the cam 1Q. all otl` which will be clearly seen by reference to Figs. 1 and Rigidly attached to the larger canryoke 15, or, if desired, made integral therewith, is the piston 17. This slides in the usual manner in a cylinder 18, secured to the body of the engine. The cylinder is provided with the usual inlet port 19, for theintake of the explosive charfre of air and hydrocar* bon, either in a mixer` state or delivered separately .to the cylinder through such inlet 19. The cylinder is also provided with an outlet port Q0, for the escape of the spent gases, and a spark plug socket 21. In the form of the invention shown in Fig. 3, the inlet port 19 connects by a passage 22 with the cam and yoke ease, in which the air is compressed to a lesser or greater degree before being delivered into the cylinder as shown, but in the form shown in Fig. 1 the inlet port 19 connects by a passage 23 with an air compressor or cylinder" 2S) exterior to the cam and yoke case but located thereon. In

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the said compression tube 29 is a piston 30, provided with a piston rod 31, the lower end of which is secured to the larger camyoke 15. In the top of the compression tube and just beneath the piston when it stands 'at its highest vposition is an inlet for the intake of free air ora mixture of free air and hydrocarbon. This air compressed either in the cam and yoke case or in the tube 29, in its free state or mingled with the vapor of any hydrocarbon7 is injected into the cylinder through the intake opening' or passage 19, and is there compressed ready tor ignition and explosion at the proper time. Ordinarily the free air and the vapor .of the hydrocarbon are delivered separately and allowed to combine they enter the engine cylinder through the passage-way 19, the velocity of the air in its passage drawing in itsl supply of the vapor of the hydrocarbon from any regulated source of supply, such as is known as a carbureter (not shown in the drawings.)

'The operation of the herein described embodiment of my invention is as follows: When the parts are in the position shown in Figs. 1 and 2, that is to say, .at the beginning of a stroke, the compressed charge in the upper part of the. cylinder is ignited, and the explosion forces the piston 17 downward. This motion is communicated to the cam-yokes 15 and 1G and thence to the cam 12, which is thereby caused to rotate, in a counter-clockwise direction. As the piston 17 descends, by reason of the explosion, or by operation by hand or otherwise, to secure the first charge to start the engine, thereby forcing the yokes 15 and 16 to the limit of their downward travel, the rod 31 and the piston 30 which are attached to the yoke 15 are drawn down and compress the contents of the cylinder 29. After the downward stroke has beencompleted, and the parts have reached the position shown in Figs. 8 and 4 the piston and the yoke. integral with it comes to a state of rest while the cam and the shaft continue to rotate for of the full rotative movement carrying at the same time the smaller yoke 16, to the inner opposite side of the larger yoke 15 from which point or location the upward movement of the yokes and the piston immediately commence. however the piston has reached the end and while it is completing the balance of its full downward stroke, the intake opening and the exhaust opening 20 in the cylinderare uncovered by the iston and thereafter remain full open while thepiston comes to a state of restduring 60 rotation of the cam, thereby giving ample time for a complete exhaust of the spent gases from the cylinder and for the delivery and full intake of thenew charge of the explosive mixture.

As soon after the piston 18 has been at rest J ust before idonea? for the 60O rotation of the cam and shaft, 1t begins toy ascend on its return stroke through the continued rotation of the cam and shaft, being impelled thereto by their own momentum and that of a fly-wheel affixed rigidly to the shaft (not shown). This fly-wheel may be located within the case if desired so` that the ends of the shaft may protrude through the ends of the cam and yoke case 11, for direct connections withoutI the intervention of such fly-wheel being between such connections and the case; preferably, it will be located exterior to the camv case. p

During the ascending and return movenient of the piston 17 it closes the intake opening 19 in the cylinder as also the exhaust opening 2O in the cylinder at its start and then with its further movement compresses the charge of the explosive mixture during such time as it takes to complete its upward or return stroke. As soon as the piston 17 has reached the limit of its upward stroke', the explosive mixture in the meantime having been compressed, .it comes to a state of rest as it did at the end of its downward- 'stroke for and during 60 rotation of the cam and shaft and while the small yoke is being 'carried vto the opposite inner side of thev larger yoke fromv where it was carried during the 60 of piston'rest at the end of its downward stroke. After such 60o of piston rest at the upper end of the cylinder, the cam (analogously crank) is on the upper dead center of the engine; after being removed a little therefrom with scarcely'any perceptible downward movement of the piston 17, the piston is in aposition to receive the force and impact of the explosion of the compressed explosive `charge when the latter is then and there ignited and caused to explode. While the piston 17 is at rest for the 60 rotation of 'the cam and shaft at the end of its upward movement the charge already compressed in the head of the cylinder has time to absorb more or less heat from the/walls and heads of the cylinder and piston that increases its pressure andA compression thereby rendering it in a state to sey re a higher power efficiency by its ex- .osion'. By the introduction of the smaller square yoke 16, the cam 12 during its rotation *causes the small yoke to horizontally travse the larger yoke from'side to side, thereb. y causing a rolling motion' of the' cam 17 against the yoke ,16, so that such pressure applied to the cam is robbed of nearly all its attendant friction that would otherwise take place if the cam was operated upon by the upper inside of the larger yoke 15 directly and withoutl the intervention of the smaller yoke 16, where a rolling action is,- now performed in lieu of an entire sliding and slipping at the central parten the under side of the upper part of the yoke. This same condition takes place when the piston is at the bottom of its stroke. When the piston is in motion in either or both of its strokes, the rolling action takes place alternately on the vertical inner sides of the small yoke and the cam. After the cam (analogously crank) has. passed the up er and lower dead center positions, the rolling'motion is transferred to the sides including the angle of the cam whereV the shaft is located, and the upper and lower insides of the small yoke. The greatest amount of friction that takes place during the engine operation is between the top and bottom outsides f the small yoke 16 and the top and bottom inner sides of the large yoke in the traversing of the small yoke from one side to the other of the large yoke. Such friction however would be mostly negligible, because proper lubrication which will be afforded, will be no greater than that between a cross-head and its sliding ways in an ordinary built steam engine properly lubricated.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is as follows:

1. The combination with an engine having a reciprocating piston therein, of a rotatable shaft and means connecting the piston and the shaft for causing the reciprocation of the former to rotate the latter, said means comprising an equilateral triangular cam secured against rotation on said shaft,

-ing a reciprocating piston therein, of a rotatable shaft and means connecting the piston andthe shaft for causing the reciprocation of the former to rotate the latter, said means comprising an equilateral triangular cam secured against rotation on said shaft, a yoke exterior to said cam, a second yoke exterior to said first-mentioned yoke, the said first-mentioned yoke being adapbedto reciprocate transversely in the said `second yoke, and means connecting said second yoke with said piston, whereby the reciprocation of the piston will continuously rotate the shaft while the piston will dwell in its reciprocatin r movement near the end of its inward stro e.

WILLIAM A. PITT.

Witnesses EuMoND CONGAR BROWN, EDMoND L. BROWN. 

